Tornado 6.5.5+ vulnerability: RequestHandler cookie attr injection via set_cookie
CVE-2026-35536 Published on April 3, 2026
In Tornado before 6.5.5, cookie attribute injection could occur because the domain, path, and samesite arguments to .RequestHandler.set_cookie were not checked for crafted characters.
Vulnerability Analysis
CVE-2026-35536 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Weakness Type
Improper Handling of Invalid Use of Special Elements
The product does not properly filter, remove, quote, or otherwise manage the invalid use of special elements in user-controlled input, which could cause adverse effect on its behavior and integrity.
Products Associated with CVE-2026-35536
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Affected Versions
tornadoweb Tornado:- Before 6.5.5 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.